Neuroleptic, antipsychotic drugs are frequently used in women during pregnancy for various purposes. These drugs are not overtly teratogenic; but many studies suggest that at least the phenothiazines, and perhaps all neuroleptics, can alter subsequent neural and behavioral development in animals which were exposed to the drug, via maternal ingestion, before or shortly after birth. Since neuroleptic drugs are highly lipid soluble chemicals they are assumed to easily diffuse from maternal to fetal blood and then into fetal brain tissue. The concentration of two neuroleptics, haloperidol and pimozide, will be measured in maternal blood and fetal brain tissue at relevant times after oral administration in order to estimate maternal-fetal transfer kinetics of these neuroleptics. Further studies will examine the effects of perinatal exposure to pimozide or haloperidol on postnatal maturation of catecholaminergic neurons in rat brain and on some aspects of behavior. These studies will provide significant information on the potential for "behavioral teratogenesis" of neuroleptic drugs.